High tension switch



OCt. 24, 1933. K FEL-TEN l 1,931,862

HIGH TENSION SWITCH Fiied May 9, 1928 iy. f

l NVE NTOR:

HTTQR NEYS.

Patented Oct. 24, 1933 PATENT y Fries HIGH TENSVION'SWITCH Karl Felton, Siegburg, Germany Application May 9, 1928, Serial No. 276,321, andy in Germany May 16, 1927 iolaim. (o1. 177-311) In the use of the high tensionA switches hither-4` toV known having oil submerged-contacts and irrespective of whether the switch is provided with horizontally guided contact bridges or with contact vdiscs rotatably arranged on a switch shaft it is notv possible during the Vworking to obtain a knowledge of the condition ofthe contact faces. A knowledge of the condition of the contact faces can be obtained only during an investigation of the switch on cutting olf the current. However it frequently occurs that the contact faces become defective during the actual working and since these defects cannot be observed in the switches while in use, such defects not infrequently result in extremely dangerous switch explosions. These explosions occur most frequently during the switching in and out of the contacts because in most of the devices hitherto employed the switching in and out takes place slowly, accompanied therefore by intense sparking.

The present invention has for its object to remove the drawbacks above mentioned. To this end according to this invention during the switching in of the main contacts, by means of special secondary contacts, a resistance arranged in parallel with the main contacts is switched insimultaneously, the arrangement being such that, in the event of any damage occurring to the main contact faces, the resistance referred to is traversed by the current, thus creating a magnetic field which during the working at once causes an appropriate signaling device to become operative. ln this way therefore a knowledge of the condition of the contact faces is indicated during the working so that the causes of any possible switch explosion may be removed at the very outset. By preference Contact discs or levers are employed and arranged so that they can be cut in or cut out during their fastest part of the movements, thereby preventing extreme sparking during the switching actions and consequently excluding the possibility of a switch explosion.

The invention is illustrated by way of example in the accompanying drawing in one form.

Fig. l is a diagrammatical representation thereof in section on theline l-l'of Figure 2.

Fig. 2 is a similar section on the line 2 2 of Figure 1. l

Fig. 3 is a broken away perspeceive View illustrating the relative angular positions of the' 4.contact faces d', c', frespectively.

turn drive the switch shaft c of the oil-charged high tension switch e. This shaft c carries'three' discs d, e andf made of insulating material and provided on part of `their circumference with `In the switched-in position illustrated in the drawing the central switch disc ey connects the main contacts g, h of the terminals Vi, 1c of the switch conductively one with theV other. The current therefore flows from the terminal i through the Contact disc e direct to the terminal lc. The contact faces d', f of the two other discs d, ;f are in practice shorter than the contact face c' of the disc e and serve solely to connect the discs 'd and f to the secondary contacts Z, m of the terminals i, lc. The contact faces d', f are connected one to the other by a resistance n. As soon therefore, during the working, as the main contact faces g or h become defective the current flows through the terminal i, not through the switch disc e,1 but over theswitch disc f and through the resistance n, which as will be seen lies inthe circuit parallel with the switch disc e and over the switch disc d to the terminal Ic. The resistance n which is wound about the switch shaft c and acts as a solenoid creates a magnetic field in the closed magnetic circuit. o thereby energizing the coil p included in said magnetic field. By connecting the coil fo to a .suitable indicating device such for instance as a bell B, Fig. 3, it is thus possible at any time during the working at once to indicate injury to the contact faces g,y h. If the main contact faces y, h are quite intact the current iiows obviously, not through the resistance n, but directly over the contact disc e, whereby the indicating device connected to the coil p remains unactuated. From the foregoing, it will be seen that the auxiliary circuit, which includes the contact members d' and f', constitutes an inductive impedance to theiiow of current through said auxiliary circuit.

The three discs d, e and f are preferably arranged so that onswitching in first of all the discs d and f are brought into contact with the secondary contacts Z, m before the main contacts g and h are closed by the switch disc e. This is accomplished by .disposing the contact members d and f' on their respective discs so that they are in staggered relation to each other and to the contact member e', the disc c of which is disposed between the discs d and f, as clearly shown in Fig. 3. By reason of this disposition the contact members d', f will close the circuit through the contact members l and 'm Lil sof

in advance of the closing of the circuit through contacts d and e by the contact member e', andwill remain closed for a short period after the main circuit through g, h has been opened. Since the contact members d and j each serve to connect with only one terminal or fixed contact member, they can be of considerably shorter length than contact member e', which alone serves to close the gap between the terminals g and h. The current therefore must :rst of all flow for a short time through the resistance n before the contact faces g and h are closedlby the contact disc e. The closing of the auxiliary circuit through the contact members'd and f" before the main circuit is closed, and maintaining said auxiliary circuit closed after the main circuit is opened, introduces an impedance which is not only effective to reduce arcing, but causes Y the switching in of the main circuit to occur at the highest speed of the discs. In other words, the contact members d', e and f are of such length and so disposed that after contact has been made they remain in contact during continued rotation of the discs about a predetermined angle, asv clearly indicated in Fig. l.Y

cause of the possibility of gradual retardation. The same is, of course, true of the opening of the switch.

In the constructional form shown the switch has only one interrupting point between the two poles i, lc. By increasing the number of switch discs the number of interrupting points could, however, beplikewise increased.

What I claim isz- A high-tension switching device, comprising in combination, a pair of xed terminals each havingla main contact and an auxiliary contact, a shaft mounted for rotation between said terminals, an insulating disc secured on said shaft and having a Contact element in position to engage both of said main contacts thereby to form a main circuit through said terminals, a pair of insulating disks secured in spaced relation onV said shaft and each having a contact element in position toengage one of said auxiliary contacts, a' low impedance element connecting the contact elements of said pair of disks thereby to form a shunt circuit through said terminals, siad contact elements being relatively so disposed that upon rotation of the shaft the shunt circuit will be closed before the main circuit and will be opened after the opening of the main circuit, said device also including means to indicate when current iiows in said impedance element.

KARL FELTEN.

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